what is dry ice ?

Question

in chemistry

Answer 1

(m)

What is Dry Ice?

Dry Ice is frozen carbon dioxide. Unlike most solids, it does not melt into a liquid, but instead changes directly into a gas. This process is called sublimation. The temperature of dry ice is around -109° F! It melts very quickly so if you need dry ice for an experiment or project, buy it as close as possible to the time you need it.


Dry Ice Safety Rules:

1) KIDS: Never use dry ice without adult supervision. Dry ice can cause serious injury if not used carefully!!!

2) Never store dry ice in an airtight container. As the dry ice melts from a solid directly into a gas, the gas will build up in the container until it bursts. Sharp pieces of container will go flying all over the place. Make sure your container is ventilated!!! The best place to store dry ice is in a styrofoam chest with a loose fitting lid.

3) Do not touch dry ice with your skin! Use tongs, insulated (thick) gloves or an oven mitt. Since the temperature of dry ice is so cold, it can cause severe frostbite. If you suspect you have frostbite seek medical help immediately.

4) Never eat or swallow dry ice! Again, the temperature of dry ice is very, very cold. If you swallow dry ice, seek medical help immediately.

5) Never lay down in, or place small children or pets in homemade clouds. The clouds are made of carbon dioxide gas! People and pets could suffocate if they breathe in too much gas.

6) Never place dry ice in an unventilated room or car. If you are traveling with dry ice in the car, crack a window open. Same rule applies if you are in a small room, crack a window open. You do not want too much carbon dioxide gas to build up around you.

7) Always wear safety goggles when doing experiments with dry ice.

8) Do not place dry ice directly on countertops. The cold temperature could cause the surface to crack.

9) Leave the area immediately if you start to pant or have difficulty catching your breath. This is a sign that you have breathed in too much carbon dioxide gas.

10) Do not store dry ice in your freezer. It will cause your freezer to become too cold and your freezer may shut off. However, if you lose power for an extended period of time, dry ice is the best way to keep things cold!


Disposing of Dry Ice:

To dispose of dry ice, place in a well ventilated container and take it outside where small children and pets cannot reach it. Simply let it sublimate away!

Answer 2

Dry ice is a very versatile substance used in the world today. It is a chemical compound consisting of frozen carbon dioxide or CO2. Dry ice changes from a solid to a gas through a process called sublimation. Sublimation makes dry ice much different than regular ice because instead of melting and making a mess, it sublimates and evaporates into the air. Dry ice has a temperature of -109.3ºF. It has twice the cooling power of regular ice.

Dry ice was discovered in 1825 by a French chemist named Thilorier. He opened a large cylinder of liquid carbon dioxide to observe its changes. When he opened the lid, he noticed much of the carbon dioxide had evaporated. He saw that there was a solid dry ice block at the bottom of the container. Throughout the next 60 years, dry ice was tested and observed by several university labs and scientists.

Dry ice has a quick and easy manufacturing process. The first step is carbon dioxide must be pressurized and refrigerated, until it changes into its liquid form. When this occurs there is an extreme drop in temperature. The extreme cold makes the liquid freeze and turn into a snow-like substance. The substance is then hydraulically pressed into either pellets or blocks of dry ice.

Answer 3

Dry Ice is frozen carbon dioxide, a normal part of our earth's atmosphere. It is the gas that we exhale during breathing and the gas that plants use in photosynthesis. It is also the same gas commonly added to water to make soda water. Dry Ice is particularly useful for freezing, and keeping things frozen because of its very cold temperature: -109.3°F or -78.5°C. Dry Ice is widely used because it is simple to freeze and easy to handle using insulated gloves. Dry Ice changes directly from a solid to a gas -sublimation- in normal atmospheric conditions without going through a wet liquid stage. Therefore it gets the name "dry ice."

Answer 4

Solid carbon dioxide, often known by the genericized trademark "dry ice", is a versatile cooling agent. Unlike water ice at atmospheric pressure it sublimes, changing from a solid directly to a gas. Its sublimation point is -78.5°C (-109.3ºF). A combination of its low temperature, solid phase and direct sublimation to gas makes it a simple and effective coolant. Dry ice is also inexpensive; it costs about US$2 per Kg (US$1 per lb).

Answer 5

What Is Dry Ice?
Dry ice is the solid form of Carbon Dioxide (CO2), which is a colorless, tasteless, odorless gas found naturally in our atmosphere. Though it is present in relatively small quantities (about 0.03% by volume), it is one of the most important gases we know of.

CO2 is a natural media that serves many life sustaining purposes. It is a key element in the carbon cycle; it is the only source of carbon for the carbohydrates produced by agriculture; it stimulates plant growth; and it helps to moderate the temperature of the earth overall. Animal respiration is believed to add 28 million tons of Carbon Dioxide per day into the atmosphere. By contrast, the U.S. CO2 industry can supply only 25,000 tons per day and 95% of this amount is from by-product sources, or less than 0.04% of the other sources combined.

With a low temperature of -109° F (-78° C), solid CO2 (dry ice) has an inherent thermal energy ready to be tapped. At atmospheric pressure, dry ice sublimates directly to vapor without going through a liquid phase. This unique property means that the blast media simply disappears, leaving only the original contaminant to be disposed of. In addition, blast cleaning in water sensitive areas is now practicable.

The grade of carbon dioxide used in dry ice blasting is the same as that used in the food and beverage industry and has been specifically approved by the FDA, the EPA and the USDA. Carbon dioxide is a non-poisonous, liquefied gas that is both inexpensive and easily stored at work sites. Of equal importance is its non-conductive and non-flammable nature.

CO2 is a natural by-product of several industrial manufacturing processes such as fermentation and petrol-chemical refining. The CO2 given off by the above production processes is captured and stored without losses until needed. When the CO2 is returned to the atmosphere during the blasting process, no new CO2 is produced. Instead, only the original CO2 by-product is released.

Answer 6

Solidified carbon dioxide that, at -78.5°C and ambient pressure, changes directly to a gas as it absorbs heat. It is used as a coolant to induce the ice phase for supercooled cloud and fog modification procedures.

Dry Ice is frozen carbon dioxide, a normal part of our earth's atmosphere. It is the gas that we exhale during breathing and the gas that plants use in photosynthesis. It is also the same gas commonly added to water to make soda water. Dry Ice is particularly useful for freezing, and keeping things frozen because of its very cold temperature: -109.3°F or -78.5°C. Dry Ice is widely used because it is simple to freeze and easy to handle using insulated gloves. Dry Ice changes directly from a solid to a gas -sublimation- in normal atmospheric conditions without going through a wet liquid stage. Therefore it gets the name "dry ice."

As a general rule, Dry Ice will sublimate at a rate of five to ten pounds every 24 hours in a typical ice chest. This sublimation continues from the time of purchase, therefore, pick up Dry Ice as close to the time needed as possible. Bring an ice chest or some other insulated container to hold the Dry Ice and slow the sublimation rate. Dry Ice sublimates faster than regular ice melts but will extend the life of regular ice.

It is best not to store Dry Ice in your freezer because your freezer's thermostat will shut off the freezer due to the extreme cold of the Dry Ice! Of course if the freezer is broken, Dry Ice will save all your frozen goods.

Commercial shippers of perishables often use dry ice even for non frozen goods. Dry ice gives more than twice the cooling energy per pound of weight and three times the cooling energy per volume than regular water ice (H2O). It is often mixed with regular ice to save shipping weight and extend the cooling energy of water ice. Sometimes dry ice is made on the spot from liquid CO2. The resulting dry ice snow is packed in the top of a shipping container offering extended cooling without electrical refrigeration equipment and connections.

Answer 7

Solid carbon dioxide, often known by the genericized trademark "dry ice", is a versatile cooling agent. Unlike water ice at atmospheric pressure it sublimes, changing from a solid directly to a gas. Its sublimation point is -78.5°C (-109.3ºF). A combination of its low temperature, solid phase and direct sublimation to gas makes it a simple and effective coolant.

Answer 8

Solid carbon dioxide is called dry ice.

Answer 9

Frozen Carbon Dioxide

Answer 10

The 2nd and 3rd answers to your question were both correct. (Who gave them a thumbs down???) The way dry ice is formed is by cooling gaseous, pressurized CO2. To understand the process you must have an understading of chemical "phase diagrams". See the link below for an excellent explanation.